Costolo spoke on the topic of "how to lead." He declined to take questions afterwards. Companies that are preparing or expecting to file paperwork with the SEC often go through "quiet periods" which restrict executives from saying anything that might prime the market. Costolo appeared to be acting in an abundance of caution prior to the S-1 filing with the SEC.

Facebook's Mark Zuckerberg had some advice for Costolo and Twitter, also at the Disrupt event: “I’ve been very outspoken about staying private as long as possible ... But in retrospect, I was too afraid of going public. I don’t think it’s necessary to do that."

Twitter just demonstrated it has robust potential revenue growthby acquiring MoPub, a mobile ad exchange/publisher network, for $350 million in stock.

Twitter funder Peter Fenton of the venture fund Benchmark is feeling confident in his portfolio of stakes, which includes a famous bet on Twitter. Benchmark contributed in two rounds that totaled $135 million, and included other funders. He wasn't addressing Twitter's IPO specifically in this recent Bloomberg piece, but hey, timing! “When I was 26 years old practicing in the venture business, I hadn’t seen enough patterns of scaling to really identify how we could best help a company ... Having invested in software for a decade, if for no other reason than you’ve done it for 10,000 hours and 10 years, you start to get good at it.”

Twitter has been in talks with banks about handling the public stock offering, according to the S.F. Chronicle. Twitter's finance chief, Mike Gupta, obviously, is leading those talks. He joined Twitter in 2012 and has public stock market experience from stints at Yahoo and Zynga.

Gupta is exactly the kind of guy you want to handle an IPO, according to Fenton. He told the Chronicle, "A lot of people are trying to understand, 'How does this thing work? How does it make money?' ... He has a layman's ability to simplify and express it in a way that's not overly complicated." Investor roadshows — where the company presents its financials to potential buyers — are a big part of IPOs.

Twitter has taken $1.16 billion in funding and those people will want their money back, plus a premium. That's such a large sum of investment for a startup that one of the only ways to get it back would be to either IPO or be acquired by an even larger company. The latter scenario didn't happen, obviously.